Add svg icons for play pause etc

src/ui/ui_icons.h

@@ -10,6 +10,10 @@ enum UI_IconID {
     UI_ICON_KNOB,
     UI_ICON_SLIDER_THUMB,
     UI_ICON_FADER,
+    UI_ICON_TRANSPORT_REWIND,
+    UI_ICON_TRANSPORT_STOP,
+    UI_ICON_TRANSPORT_PLAY,
+    UI_ICON_TRANSPORT_RECORD,
     UI_ICON_COUNT
 };